How to Select the correct frequency spectrum profile during the configuration of the VDSL2 line profile?
1. The 17a and 30a profiles are used in short-haul applications (Generally the distance is no greater than 300 m). In fact, the 30a profile is rarely used. Currently, the 17a profile is used in short-haul applications.
2. The 12a, 12b, 8c, and 8d profiles are used in medium-haul applications (generally the distance is from 300 m to 1 km).
The 8a and 8b profiles are used in long-haul applications (the distance is greater than 1 km). They are compatible with ADSL2 and ADSL2+, and suitable for central offices (The 8a profile can provide a transmit power of 20.5 dBm, the same as in ADSL2+.). The coverage range can exceed 3 km and is close to the coverage range of ADSL2+.
3. When the distance is greater than 1.5 km, the rate curve of the VDSL2 overlaps with that of the ADSL2+. In the distance from 1 km to 1.5 km, the rate advantages of the VDSL2 are not obvious. Therefore, the main coverage range of the VDSL2 is still less than 1 km.
4. The 12a, 17a, and 30a profiles are especially suitable for short-and-medium-haul applications, such as FTTN, FTTC, and FTTB. Take the 12aB8-4 as an example. The uplink can be at least 10 Mbit/s over a copper cable whose diameter is 0.4 mm within a distance of 500 m, 5 Mbit/s within a distance of 700 m, and 1 Mbit/s within a distance of 1 km (24 VDSL2 lines with self-crosstalk). The downlink rate can be 30 Mbit/s over a copper cable whose diameter is 0.4 mm within a distance of 500 m, 20 Mbit/s within a distance of 700 m, and 18 Mbit/s within a distance of 1 km (24 VDSL2 lines with self-crosstalk). If the 17a or 30a profile is used, the rate can be 30 Mbit/s or 100 Mbit/s in the uplink, and 50 Mbit/s or 100 Mbit/s in the downlink within a distance of 300 m.
In practical application, the profiles can be flexibly chosen. The profiles given in this case are for reference only.